A group of
prehistoric people mastered a difficult and delicate process to sharpen
stones into spears and knives at least 75,000 years ago, more than
50,000 years earlier than previously thought, according to a report.

This technique, known as
pressure flaking, allowed for the more precise shaping of stones to
turn them into better weapons for hunting, a paper published on
Thursday in the U.S. periodical Science said.